Multi-station document inserting machines generally include a plurality of various stations which are configured for specific applications. Typically, such inserting machines, also known as console inserting machines, are manufactured to perform operations customized for a particular customer. Such machines are known in the art and are generally used by organizations which make up large volume mailings where the content of each mail piece may vary.
An example of a document inserting machine is disclosed in U.S. Pat. No. 4,547,856 issued to Piotroski, et al. on Oct. 15, 1985 and assigned to the assignee of the present invention. This inserting machine includes a plurality of serially arranged stations including an envelope feeder and insert station, a plurality of insert feeder stations and a burster-folder station. There is a computer generated forms or web feeder that feeds continuous form control documents having control coded marks printed thereon to the burster-folder station for separating and folding. The control marks on the control documents are sensed by a control scanner located in the burster-folder station. Thereafter, the serially arranged insert feeder stations sequentially feed the necessary documents onto a transport deck at each station as the control document arrives at the respective station to form a precisely collated stack of documents which is transported to the envelope feeder-insert station where the stack is inserted into the envelope.
Generally, control documents are fed in a predetermined orientation, i.e., landscape or portrait, that facilitates a fixed beam scanner reading control marks on the moving documents. In certain applications, after the control marks are read, it is necessary to convey the documents in the other orientation for further processing, such as insertion into an envelope. One conventional way for achieving landscape to portrait, or portrait to landscape change in orientation of sheets as they are conveyed through an inserting machine includes a first paper path conveying to a distinct second paper path. The first paper path, conveying in a first direction, ends at a second paper path which is typically orthogonal to the first paper path and conveying in a second direction. Generally, the conveying means of the second paper path does not begin to convey until the sheet has been transferred from the first paper path to the second paper path. Such an arrangement ensures the proper orientation of the sheet being conveyed in the second direction but reduces the throughput of the inserting machine.
In U.S. Pat. No. 5,180,154, issued Jan. 19, 1993 and assigned to the assignee of the present invention, a right angle transfer device is disclosed. The transfer device changes the direction of travel of a flat article being conveyed at a high speed, e.g. 100 inches/second, without turning the article. The device includes a take away unit which receives the article being conveyed in a first direction, and conveys the article in a second direction, preferably 45.degree. from the first direction, to a registration wall extending in a third direction which is orthogonal to the first direction. A third direction conveying means conveys the article for further processing. Although the right angle transfer device is suitable for changing the direction of travel of flat articles having a certain thickness or rigidity, the device has not suitable for changing the direction of single sheets being conveyed at a high speed. Specifically, the single sheets tend to crash into the registration wall at high speed resulting in a crumpling of the sheet and a subsequent paper jam.
U.S. Pat. No. 5,188,355, issued Feb. 23, 1993 and assigned to the assignee of the present invention, provides an apparatus for changing the direction of travel of sheets of paper being conveyed seriatim along a paper path without changing the orientation of the sheets with respect to a first direction of travel. The apparatus comprises a deck having an upstream end for receiving a sheet being conveyed along a paper path in a first direction. There are a plurality of first roller pairs operatively coupled to the deck and disposed in a second direction for seizing a first leading edge of the sheet and conveying the sheet in the second direction along the deck. The second direction forms an acute angle of at most 45.degree. with the first direction. It is noted in U.S. Pat. No. 5,188,355 that conveying individual sheets at a high speed, for example, 105 inches per second, through the transfer unit to an alignment unit causes portions of a sheet to lift off of the deck unless such sheet portions are restrained. A plurality of guide fingers are operatively coupled to the first roller pairs to prevent a portion of each sheet from raising off the deck when the portion is not controlled by the first roller pairs. The alignment unit includes a plurality of second roller pairs which are operatively coupled to the deck and disposed in a third direction for seizing a second leading edge of the sheet and conveying the sheet in the third direction along the deck. The third direction forms a right angle with the first direction. The first and second roller pairs include lower driven rollers and upper biased rollers. The guide fingers include a plurality of spring structure for preventing a portion of the sheet from lifting off the deck when being conveyed at high speed. The apparatus is suitable for conveying sheets landscape to portrait or portrait to landscape.
The apparatus in U.S. Pat. No. 5,188,355, eliminated the problem associated with a registration wall in U.S. Pat. No. 5,180,154. However, another problem has been experienced relating to the spring guide fingers. The guide fingers improved the performance of the apparatus without fingers, but jams were still experienced because, notwithstanding the guide fingers, the sheets have a propensity to lift off the deck as they are conveyed at high speed through the apparatus. In particular, jams were experienced between the transfer unit and the alignment unit of the apparatus as the sheets are engaged by the second roller pairs. Thus, the number and placement of the guide fingers are directly related to the reliability of sheets being successfully fed through the apparatus. Furthermore, it was determined that the number of fingers needed and the placement thereof may differ for different sized sheets, thus requiring adjustments whenever the type of sheets being fed changed. Alternate methods, such as a brush or guide wires, are disclosed in application 816,442 for restraining the sheets from lifting off the deck.